1. Field of the Disclosure
This disclosure relates generally to apparatus for use in wellbore operations utilizing progressive cavity power devices.
2. Background of the Art
To obtain hydrocarbons, such as oil and gas, boreholes or wellbores are drilled by rotating a drill bit attached to a drill string end. A large proportion of the current drilling activity involves drilling deviated and horizontal boreholes to increase the hydrocarbon production and/or to withdraw additional hydrocarbons from the earth's formations. Current drilling systems utilized for drilling such wellbores generally employ a drill string having a drill bit at its bottom that is rotated by a motor (commonly referred to as a “mud motor” or a “drilling motor”). A typical mud motor includes a power section that includes a rotor having an outer lobed surface disposed inside a stator having an inner lobed surface. Such a device forms progressive cavities between the rotor and stator lobed surface. Such motors are commonly referred to as progressive cavity motors or Moineau motors. Also, certain pumps used in the oil industry utilize progressive cavity power sections. The stator typically includes a metal housing lined inside with a helically contoured or lobed elastomeric material. The rotor typically includes helically contoured lobes made from a metal, such as steel. Pressurized drilling fluid (commonly known as the “mud” or “drilling fluid”) is pumped into progressive cavities formed between the rotor and stator lobes. The force of the pressurized fluid pumped into the cavities causes the rotor to turn in a planetary-type motion.
The disclosure herein provides progressive cavity motors and pumps wherein a section of the rotor or stator is made from or lined with an elastomeric to provide sufficient seal between the rotor and stator and one or more sections of both the rotor and motor are made from or lined with a metallic material to reduce the load on the elastomeric material.